Diffusion Coefficient of n-alkanes in Heavy Oil

Guerrero-Aconcha, Uriel Enrique; Salama, Dalia; Kantzas, Apostolos

doi:10.2118/115346-ms

Cited by 23 publications

(23 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although it cannot be guaranteed that the same correlation found for only one third of the concentration range can be used to the whole range, one can get an indication of the diffusion coefficients at higher concentrations, using extrapolation of the experimental data. For instance, one can find an estimated value of 4.5 × 10 −7 cm 2 /s for the infinite dilution of hexane in bitumen when the bitumen concentration is 100%, which is in the same order of 7.81 × 10 −7 cm 2 /s reported by Guerrero‐Anoncha et al for a hexane‐heavy oil system at 298.15 K. It is stressed that the contribution of this part of our work is not the values themselves, but the obvious decreasing trend of the diffusion coefficient with increased bitumen concentration. This trend is in line with the theory, as well with the experimental observations reported by Guerrero‐Anoncha et al for the heavy oil concentration range of 20–100%, where they used an X‐ray computed tomography in situ measurement technique and analyzed the measured concentration profiles through the slope‐intercept approach …”

Section: Resultssupporting

confidence: 80%

“…Following this presumption, the adjustment yielded a value of 1.26 × 10 −5 cm 2 /s, which was in the range of our measured diffusion coefficients. Guerrero‐Aconcha et al extrapolated their measured diffusion coefficients over the hexane concentration range of 0–80% for heavy oil with a viscosity of 6000 mPa s and found an infinite‐dilution diffusion coefficient of 1.71 × 10 −5 cm 2 /s at 298.15 K. Although it was not measured directly, the extrapolated value was not significantly different from our measured value of 1.59 × 10 −5 cm 2 /s for the unfiltered bitumen solution, considering a much higher bitumen viscosity and a slightly higher experimental temperature in our case.…”

Section: Resultssupporting

confidence: 44%

“…. However, in other techniques, the molecular diffusion coefficient cannot be considered as a constant for the designed experiments and, thus, the analysis would be more complex and demanding, introducing unwanted errors in the concentration dependency trends . Therefore, the results demonstrated here are free from inherent analysis error involved in other analysis techniques and can be considered as the actual physical behavior of the system.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Ghanavati

Abedi

2014

AIChE Journal

View full text Add to dashboard Cite

A novel approach with fewer technical and analytic limitations in liquid solvent-bitumen diffusion studies is used in this article. The Taylor dispersion technique was selected for its convenient short run time experiments and reliable data analysis to find mutual diffusion coefficients in a hexane 1 bitumen mixture. For the first time, the infinite-dilution molecular diffusion coefficients of bitumen in hexane were measured in both the presence and relative absence of asphaltene particles in the solution at atmospheric pressure and temperatures of 303.15, 310.15, and 317.15 K. The polydisperse nature of bitumen was clearly revealed. Results were compared with common predictive tools. Also, the asphaltene surface charge in the hexane precipitating solvent was demonstrated. Through concentration dependency investigations at atmospheric pressure and 303.15 K, it was determined that the mutual diffusion coefficients monotonically decrease as the viscosity of mixture increases within the studied 0-34% volumetric concentration of bitumen. The Taylor dispersion technique shows great potential for diffusion studies of liquid solvent-bitumen systems.

show abstract

Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 44%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Ghanavati

Abedi

2014

AIChE Journal

View full text Add to dashboard Cite

show abstract

“…Diffusion coefficients were calculated using the slopes and intercepts method (Sarafianos, 1986;Guerrero-Aconcha et al, 2008). The output from this solution technique is the diffusion coefficient of solvent into bitumen, which is expressed as a function of solvent content.…”

Section: Figure 5-mass Transfer Of Different Liquid Solvents Into Peamentioning

confidence: 99%

Evaluation of Diffusion of Light Hydrocarbon Solvents in Bitumen

et al. 2015

View full text Add to dashboard Cite

Solvent-based processes are often used as potential recovery agents in bitumen systems, with and without the addition of heat to the solvent. Solvents can sometimes be applied as a liquid phase, during SAGD start-up operations or processes aimed at developing injectivity into the oil. Light hydrocarbon liquids are traditionally tested for this application. Solvent injection may also occur in a vapour state and its objective is to reduce oil viscosity and improve mobility of bitumen under low temperatures Ͻ100°C. In general, hydrocarbon solvents such as propane are often used for this application. The objective of this study is to conduct CT-based measurement of static mixing of bitumen and both liquid and vapour phase solvents, and to quantify some of the time-dependent changes that occur during solvent mixing with bitumen.Diffusion experiments have been conducted with propane and DME (vapour phase) and with propane, DME, pentane and toluene (liquid phase) solvent systems. Solvents are mixed with medium viscosity Peace River bitumen and high viscosity Grosmont bitumen. The Tests are run under constant pressure and temperature, and Computer-Assisted Tomography (CT) is used to monitor mass transfer of solvent into oil as a function of time. The outcome of this study is measurements of mass transfer rates of solvent into oil, and the degree of oil phase swelling during the tests.During solvent injection processes in the field, the rate of mixing is a key parameter that will help in deciding which solvent is optimal for different processes. This study focuses on the rate of solvent mixing with oil. In vapour phase solvent systems, the analysis of the CT images allows for an understanding of the impact of oil phase swelling on the effective rate of penetration of solvent into oil. Overall, the test data provided in this work demonstrates that DME mixes into oil faster than other solvents, and leads to more swelling in a vapour solvent-bitumen system. The analysis of CT data provides an understanding of concentration-dependent diffusion coefficients and limitations from predicting mass transfer using constant coefficients in liquid and vapour solvent systems.

show abstract

“…Wen et al [40] and Afsahi [41] utilized the nuclear magnetic resonance (NMR) method to estimate the diffusion coefficients in bitumen and solvent mixtures. Guerrero-Aconcha et al [42] used CAT to obtain the density profiles and then back-calculated the concentration-dependent diffusion coefficients. Wen et al [43] used the two nondestructive methods of NMR and CAT to determine the solubility profile inside a solvent and heavy oil system.…”

mentioning

confidence: 99%

The Effect of Oil Properties on the Supercritical CO2 Diffusion Coefficient under Tight Reservoir Conditions

Zhang

Qiao

et al. 2018

Energies

View full text Add to dashboard Cite

In this paper, a generalized methodology has been developed to determine the diffusion coefficient of supercritical CO 2 in cores that are saturated with different oil samples, under reservoir conditions. In theory, a mathematical model that combines Fick's diffusion equation and the Peng-Robinson equation of state has been established to describe the mass transfer process. In experiments, the pressure decay method has been employed, and the CO 2 diffusion coefficient can be determined once the experimental data match the computational result of the theoretical model. Six oil samples with different compositions (oil samples A to F) are introduced in this study, and the results show that the supercritical CO 2 diffusion coefficient decreases gradually from oil samples A to F. The changing properties of oil can account for the decrease in the CO 2 diffusion coefficient in two aspects. First, the increasing viscosity of oil slows down the speed of the mass transfer process. Second, the increase in the proportion of heavy components in oil enlarges the mass transfer resistance. According to the results of this work, a lower viscosity and lighter components of oil can facilitate the mass transfer process.Energies 2018, 11, 1495 2 of 20 methods for the quantitative determination of the gas (N 2 , CO 2 , CH 4 [28], C 2 H 6 , C 3 H 8 , or a mixture gas) diffusion coefficient in crude oil. These methods include the pressure decay method, X-ray computer-assisted tomography (CAT) method, magnetic resonance imaging (MRI) method [29,30], dynamic drop volume analysis (DPDVA), and pore-scale network modeling method. All of these methods have advantages and flaws:Direct testing method. Hill and Lacey [31] tested the diffusion coefficient of CH 4 in isopentane with a constant pressure method in a Pressure-Volume-Temperature (PVT) system. Sigmund [32] also used this method to study the binary dense gas diffusion coefficients under reservoir conditions. Islas-Juarez et al. [33] set up an experimental device to determine the effective diffusion coefficient of N 2 in a sandpack model. They devised a special setting to sample crude oil that was dissolved with N 2 in their porous model. The samples were then analyzed by gas chromatograph, and the gas concentration in the oil phase was determined. The corresponding diffusion coefficient was determined by matching the mathematical diffusion model with the experimentally measured concentration curve. The main shortcomings of the direct testing method for the solvent diffusion coefficient are that it is both time and labor consuming, which results in an expensive process.Pressure decay method. Riazi [34] proposed a technique known as the pressure decay method based on the fact that the pressure of the gas phase in a closed diffusion cell decreases with the migration of the gas phase into the liquid phase. One of the remarkable features of this method is that it does not require costly component measurements. In the following two decades, many scholars adopted this method to test the diffus...

show abstract

Diffusion Coefficient of n-alkanes in Heavy Oil

Cited by 23 publications

References 77 publications

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Application of taylor dispersion technique to measure mutual diffusion coefficient in hexane + bitumen system

Evaluation of Diffusion of Light Hydrocarbon Solvents in Bitumen

The Effect of Oil Properties on the Supercritical CO2 Diffusion Coefficient under Tight Reservoir Conditions

Contact Info

Product

Resources

About